Method of recognizing touch

ABSTRACT

The disclosure relates to a method for recognizing touch. A first value T 1  and a second value T 2  are set. A maximum sensing value C peak  is obtained. A position of the C peak  is defined as a sensing position A. Sensing values C 1 , C 2 , C 3 , and C 4  of four neighboring sensing positions are obtained. C peak  is compared with T 1  and T 2 . When C peak  is greater than or equal to T 1 , a touch with finger is recognized. When C peak  is smaller than T 2 , no touch is recognized. When C peak  is greater than or equal to T and smaller than T 1 , following steps are taken. A third value T 3  is set. A first total sensing value C t  of C 1 , C 2 , C 3 , and C 4  is compared with T 3 . When C t  is greater than or equal to T 3 , a touch with glove is recognized. When C t  is less than T 3 , no touch is recognized.

This application claims all benefits accruing under 35 U.S.C. §119 from China Patent Application No. 201310314149.2, filed on Jul. 25, 2013 in the China Intellectual Property Office, the contents of which are hereby incorporated by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to a method of recognizing touch on a touch panel and particularly a method of recognizing touch on a capacitive touch panel.

2. Description of Related Art

In recent years, various electronic apparatuses such as mobile phones, car navigation systems have advanced toward high performance and diversification. There is continuous growth in the number of electronic apparatuses equipped with optically transparent touch panels in front of their display devices such as liquid crystal panels. A user of such electronic apparatus operates it by pressing a touch panel with a finger or a stylus while visually observing the display device through the touch panel.

According to working principle and transmission medium, touch panel has four types of resistance, capacitance, infra-red, and surface acoustic-wave. Capacitive touch panel has been widely used for its higher sensitivity and lower touch pressure required.

Working principle of capacitive touch panel is as follows: distribution of capacitance on the touch panel is changed by a finger touch, the change of distribution of capacitance is detected and a touch position is obtained. However, if the finger is coated by an insulator such as gloves, the touch cannot be recognized, thereby causing inconvenience to users.

What is needed, therefore, is a method of recognizing touch that can overcome the above-described shortcomings.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the embodiments can be better understood with references to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a structure view of a touch panel.

FIG. 2 is a flowchart of a method of recognizing touch on a touch panel.

FIG. 3 is a view of signal values of a touch panel detected by an integrated circuit (IC).

DETAILED DESCRIPTION

The disclosure is illustrated by way of example and not by way of limitation in the fingers of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one.

The method of recognizing touch can be applied on all kinds of mutual-inductance capacitive touch panels. Referring to FIG. 1, a mutual-inductance capacitive touch panel comprises a driving layer 12, a sensing layer 14, and an integrated circuit (IC). The IC is electrically connected with the driving layer 12 and the sensing layer 14. The driving layer 12 is spaced from and opposite to the sensing layer 14.

The driving layer 12 comprises a plurality of driving electrodes 120. The plurality of driving electrodes 120 are spaced from each other and extend along an X direction. The sensing layer 14 comprises a plurality of sensing electrodes 140. The plurality of sensing electrodes 140 are spaced from each other and extend along a Y direction. The X direction is substantially perpendicular to the Y direction. The plurality of sensing electrodes 140 are insulated with the plurality of driving electrodes 120. The plurality of sensing electrodes 140 intersect with the plurality of driving electrodes 120 to define a plurality of sensing positions. A plurality of mutual-inductance capacitance can be formed between the plurality of sensing electrodes 140 and the plurality of driving electrodes 120. In one embodiment, the plurality of sensing electrodes 140 are parallel with each other and the plurality of driving electrodes 120 are parallel with each other The plurality of sensing electrodes 140 and the plurality of driving electrodes 120 are strip-shaped electrodes. Material of the plurality of sensing electrodes 140 and the plurality of driving electrodes 120 can be indium tin oxide or carbon nanotube.

The plurality of driving electrodes 120 are labeled by an m in order. The m is a natural number. The IC comprises a driving IC and a sensing IC. The driving IC is electrically connected with the plurality of driving electrodes 120. The driving IC is used to provide driving signals to the plurality of driving electrodes 120. The sensing IC is electrically connected with the plurality of sensing electrodes 140. The plurality of sensing electrodes 140 are used to detect signal values via the plurality of sensing electrodes 140.

Referring to FIG. 2, the method of recognizing touch comprises following steps:

-   -   S1, setting a first value T₁ and a second value T₂, wherein the         second value T₂ is smaller than the first value T₁;     -   S2, sensing touch signals and obtaining a maximum signal value         C_(peak), defining a position of the maximum signal value         C_(peak) as a sensing position A, and obtaining signal values         C₁, C₂, C₃, and C₄ of four sensing positions adjacent to the         sensing position A;     -   S3, comparing the maximum signal value C_(peak) with the first         value T₁ and the second value T₂, when the maximum signal value         C_(peak) is greater than or equal to the first value T₁,         recognizing as a touch with finger; when the plurality of first         signal values C₁ is smaller than the second value T₂,         recognizing as no touch; and when the plurality of first signal         values C₁ is greater than or equal to the second value T₂ and         smaller than the first value T₁, further taking following steps;     -   S4, setting a third value T₃;     -   S5, defining a first total value C_(t) of the first maximum         signal value C_(peak) and the signal values C₁, C₂, C₃, and C₄,         and comparing the first total value C_(t) and the third value         T₃, when the first total value C_(t) is greater than or equal to         the third value T₃, recognizing as a touch with glove; and when         not, recognizing as no touch.

In step (S1), the first value T₁ can be a threshold value of sensing signal of a traditional capacitive touch panel. In one embodiment, a maximum signal value is sensed by the sensing IC when the finger completely contacts the touch panel, and the first value T₁ is defined as one fifth to one third times of the maximum signal value.

In one embodiment, the second value T₂ is greater than a background signal value. The background signal value is a parasitic capacitance with no touch. The background signal value is caused by conductive wires connecting with the IC.

In step (S2), the plurality of sensing electrodes 140 intersect with the plurality of driving electrodes 120 and the plurality of sensing positions are formed. In one embodiment, a coordinate of the sensing position A is defined as (X_(A), Y_(A)), and coordinates of four sensing positions adjacent to the sensing position A are defined as (X_(A−1), Y_(A)), (X_(A+1), Y_(A)), (X_(A), Y_(A−1)), and (X_(A), Y_(A+1)).

The plurality of driving electrodes 120 are driven by the driving IC. The plurality of driving electrodes 120 can be driven one by one in order, or some of the plurality of driving electrodes 120 are driven simultaneously each time. Signal value is a difference value between signal values at one position of the touch panel when the touch panel is touched and not touched.

In step (S3), when the plurality of first signal values C₁ are greater than or equal to the second value T₂ and smaller than the first value T₁, the following step (S4) to step (S5) are taken in order to recognize whether it is no touch or a touch with glove, and not to be recognized as no touch directly.

In step (S4), a second maximum signal value C′ is sensed by the sensing IC when the finger with glove completely contacts a sensing position B of the touch panel. A second total value C″ is defined by adding the second maximum signal value C′ and four signal values of four sensing positions adjacent to the sensing position B. The third value T₃ is defined to one fifth to one third times of the second total value C″.

In step (S5), the touch with glove means an insulator such as the glove is existed between the screen and the finger. It is further determined whether it is the touch with glove by comparing the total value C_(t) with the third value T₃. When the total value C_(t) is smaller than the third value T₃, it is determined that the finger has a long distance with the screen or the background signal is recognized. When the total value C_(t) is greater than or equal to the third value T₃, it is determined as the touch with glove.

“False touch” means that the finger does not touch the screen actually and is just near the screen. When the distance between the screen and the finger is about a thickness of glove, the sensing IC would sense this “false touch.” If the touch is the “false touch”, the finger could not keep static during the time period and would move away from the screen. Therefore, following substeps (S31) to (S34) are further taken before step (S4) in order to prevent recognizing as the “false touch”:

S31, setting a time period;

S32, driving the plurality of driving electrodes 140 several times and sensing a plurality of third signal values during the time period;

S33, selecting a maximum signal value C′_(peak) from the plurality of third signal values of each time to obtain a plurality of maximum signal values C_(′peak), and calculating an averaged signal values C′_(peak) of the plurality of maximum signal values C′_(peak), when the plurality of maximum signal values C′_(peak) satisfy following formula: 0.8 C′_(peak) ≦C′_(peak)≦1.2 C′_(peak) , going to the steps (S4) to (S6); and when not, recognizing as no touch.

In step (S31), the time period ranges from one second to four seconds.

In step (S32), the plurality of driving electrodes 140 is driven one by one each time.

In step (S33), the touch can be two types of fixing and sliding. The fixing touch means the finger touches on a same position during the time period, and the plurality of maximum signal values C′_(peak) are equivalent. The sliding touch means the finger moves on the screen during the time period, and the plurality of maximum signal values C′_(peak) change with touching positions.

When the finger touches a position of one of the plurality of sensing electrodes 140, the signal value is great; when the finger touches a position between adjacent two of the plurality of sensing electrodes 140, the signal value is small. Therefore, the maximum signal values C′_(peak) of several times are obtained and the averaged signal values C_(peak) of the plurality of maximum signal values C′_(peak) of several times are calculated.

The method of recognizing touch has following advantages. Both the touch with finger and the touch with glove are recognized via this method. Some other errors of recognizing touch by mistake could be excluded.

It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure. 

What is claimed is:
 1. A method of recognizing touch on a touch panel, wherein the touch panel comprises a plurality of driving electrodes and a plurality of sensing electrodes, the plurality of driving electrodes intersect with the plurality of sensing electrodes to define a plurality of sensing positions, and the method comprising: setting a first value T₁ and a second value T₂, wherein the second value T₂ is smaller than the first value T₁; sensing touch signals and obtaining a maximum signal value C_(peak), defining a position of the maximum signal value C_(peak) as a sensing position A, and obtaining signal values C₁, C₂, C₃, and C₄ of four sensing positions adjacent to the sensing position A; comparing the maximum signal value C_(peak) with the first value T₁ and the second value T₂, when the maximum signal value C_(peak) is greater than or equal to the first value T₁, recognizes as a touch with finger; when a plurality of first signal values C₁ is smaller than the second value T₂, recognizes as no touch; and when the plurality of first signal values C₁ is greater than or equal to the second value T₂ and smaller than the first value T₁, taking following steps: setting a time period; driving the plurality of driving electrodes several times and sensing a plurality of third signal values during the time period; selecting a maximum signal value C′_(peak) from the plurality of third signal values of each time to obtain a plurality of maximum signal values C_(1peak), and calculating an signal values C′_(peak) of the plurality of maximum signal values C′_(peak), when the plurality of maximum signal values C′_(peak) satisfy following formula: 0.8 C′_(peak) ≦C′_(peak)≦1.2 C′_(peak) , going to the step of setting the third value T₃; and when not, recognizes as no touch; setting a third value T₃; defining a first total value C_(t) by adding the maximum signal value C_(peak) with the signal values C₁, C₂, C₃, and C₄, and comparing the first total value C_(t) and the third value T₃, when the first total value C_(t) is greater than or equal to the third value T₃, recognizes as a touch with glove; and when the first total value C_(t) is less than the third value T₃, recognizes as no touch.
 2. The method of claim 1, wherein the first value T₁ is defined as one fifth to one third times of a maximum signal value of sensing when a finger completely contacts the touch panel.
 3. The method of claim 1, wherein the second value T₂ is greater than a background signal value.
 4. The method of claim 1, wherein a second maximum signal value C′ is sensed when the finger with glove completely contacts a sensing position B of the touch panel, a second total value C″ is defined by adding the second maximum signal value C′ and four signal values of four sensing positions adjacent to the sensing position B, and the third value T₃ is defined as one fifth to one third times of the second total value C″.
 5. The method of claim 1, wherein the time period ranges from one second to four seconds. 